Webb’s segmented primary mirror has a diameter of 6.6 meters (21.7 feet). Each of the 18 segments is 1.32 meters (4.3 feet) across. The area of the mirror is approximately 25 square meters (270 square feet) and the mass is 705 kilograms (1,550 pounds on Earth)
Expected lifespan of the Webb telescope
Webb is designed to have a minimum five years of science operations, with the goal of having an overall mission lifetime greater than 10 years.